Analysis of relative wavelength response characterization and its effects on scanned-WMS gas sensing

Our recently proposed three-step method showed the promising potential to improve the accuracy of relative wavelength response(RWR) characterization in the wavelength-modulation spectroscopy(WMS) over the commonly used summation method.A detailed comparison of the three-step method and the summation method,for the wavelength-scanned WMS gas-sensing,was performed with different laser parameters(modulation indexes and scan indexes) and gas properties(pressures and concentrations).Simulation results show that the accuracy of the predicted gas parameters is strongly limited by the RWR characterization with large modulation index and high gas pressure conditions.Both fitting residuals of RWR and errors of predicted gas parameters from the recently proposed three-step method are nearly 2 orders of magnitude smaller than those from the summation method.In addition,the three-step method is further improved by introducing a coupling term for the 2^(nd) harmonic amplitude.Experiments with CO_(2) absorption transition at 6976.2026 cm^(-1) were conducted and validated the simulation analysis.The modified-three-step method presents an improved accuracy in RWR description with at least 5% smaller fitting residual for all conditions compared with the three-step method,although the deviation of the deduced CO_(2) concentrations between these two methods does not exceed 0.2%.

Association between the related characters of hemispatial neglect and prognosis in stroke patients

OBJECTIVE： To recognize the significances of the classification, evaluation, treatment, pathogenesis, etiological factors and related loci of hemispatial neglect （HSN） in the treatment and prognosis of stroke patients. DATA SOURCES： Articles related to HSN in stroke published in English from January 1985 to December 2002 were searched in Medline database by using the keywords of ＂stroke, hemispatial neglect （HSN）, rehabilitation＂. Chinese relevant professional works and articles were also referred to. STUDY SELECTION： The data were primarily checked. Inclusive criteria： ① articles about the HSN symptoms in stroke; ② articles about the classification, evaluation, treatment, pathogenesis, etiological factors and related loci of HSN, as well as the treatment and prognosis of stroke. The repetitive studies or reviews were excluded. DATA EXTRACTION ： Totally 474 articles related to HSN in stroke were collected, 43 of them were involved and 431 repetitive studies or reviews were excluded. DATA SYNTHESES： HSN can be classified as sensory neglect and motor neglect. Because HSN is caused by the injury of network structure which mediated directed attention, it is generally believed that the inferior parietal Iobule of dominant hemisphere is the most closely correlated with neglect. The main theories related to the pathogenesis of HSN at present include ＂internal instruction＂, ＂directed bradykinesia＂, ＂sensory attention＂, etc. The main clinical manifestations are setover in drawing lines, picture drawing towards one side, imitation towards one side, picture description towards one side, etc., which can be evaluated by the line bisection test, target cancellation test, picture drawing test and pegboard test. The most important thing for the treatment is to make the patients continuously concentrate on the neglected side. CONCLUSION： HSN is an indicator for the bad outcome of cerebrovascular disease, the symptoms take longer time to rehabilitate with slow recovery, but quite a few HSN patients will get good prognosis if timely treatment and proper program are given.